High speed fault tolerant mass storage network information server

ABSTRACT

The information server system incorporates a high speed, microcomputer based server running industry standard operating system software enhanced to include functionality directed to operation of a new disk array controller, which controls the physically independent or integral disk storage device array, and communications interface. The disk array controller subsystem controls and communicates with the disk storage device array with a Fibre Channel protocol. The disk storage device array incorporates a plurality of disk storage devices with a corresponding number of bypass interface cards configured to facilitate the on-line addition, removal and replacement of disk storage devices. In additional to incorporating the above described buses and Fibre Channel capability, the disk array further incorporates a physically independent Fibre Channel compatible optical bus for high speed, communication between disk storage device array subsystem components, including the internal disk storage devices, independent from the information server. A wide array of user reconfigurable options are available as well as a scalable expansion capability.

RELATED APPLICATIONS

This application is based upon Provisional Patent Application Ser. No.60/077,643, filed Mar. 10, 1998.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a “plug and play”, high speed, microcomputerbased, Fibre Channel compatible and fault tolerant mass storageinformation server system. In particular, the present invention relatesto a device and method for providing an enterprise-wide informationserver system which incorporates a dual loop arbitrated, Fibre Channelcapable, multiple-fault tolerant, hot-swappable disk array requiring nohost computer.

2. Description of the Prior Art

Efforts have been made in the past to provide a mass storage file servercapable of delivering information throughout an enterprise with highspeed data throughput, scalable data storage capability in a convenient,easily configurable enclosure using well known, industry standardoperating software. However, such systems have typically experiencedmany shortcomings and problems associated with the inability ofpresently available computer and communications hardware to sustainperformance and survive failure of component devices. Such shortcomingshave included the lack of capability to allow for scalability toaccommodate increased storage requirements without the need tocompletely power down information server system to facilitateinstallation of additional disk storage devices or communicationscapability. One of the solutions presently available requires that theentire information server system be taken off-line and powered downbefore any additional disk storage devices can be added to the diskstorage array. This and other comparable or more capable server systemsrequire a significant amount of system administrator personnel time andserver system resources to facilitate system maintenance for expansionof storage space, repair, and routine maintenance such as optimizationand system health monitoring.

Other problems existing in the presently available information serversystems include a general inability of the present technology to providecontinuous information server capability after some predetermined numberof failures have occurred in the server system. Some prior artinformation server systems have provided a limited fault tolerancecapability. Such systems typically employ a disk array server whichincorporates extra disk space substantially in excess of that needed bythe enterprise serviced by the information server system. The extra diskspace is incorporated into such systems with the addition of additionalphysical disk storage devices which are configured with a particularlogical disk drive configuration tailored to meet the storage, faulttolerance and server requirements of the user.

To accomplish a desired level of fault tolerance, the disk arraysubsystem is configured with various types of operating system softwareto create duplicate and multiple copies of the data stored on theinformation server system across various different combinations of thephysical and logical disk drives. Any of a large array of fault tolerantdisk array architectures are typically employed including, for example,various implementations of what is known the trade as the redundantarray of independent disks or “RAID” topologies and protocols. Upondetection of a complete or partial failure of a particular disk storagedevice, the operating system software program notifies the server of thefailure, marks the portion of the disk which failed or logically removesthe completely failed disk storage device from the disk array. Next, theoperating system typically reallocates the remaining available physicaldisk space into a modified configuration of logical disk drives.

The operating system then reconstructs new duplicate, multiple copies ofthe data stored on the server system within the constraints of the newlyreduced amount of free disk space. The server system also alerts theserver system administrator that a failure has occurred so thatcorrective action may be taken.

Depending on the exact nature of the failure, the necessary correctiveaction can include removal and replacement of the completely orpartially failed disk storage device. The remove and replace systemmaintenance operation requires, in many systems, that the entire serversystem be taken off-line and powered down before the physicalreplacement operation can be performed. Some information server systemspermit removal and replacement of the defective disk storage devicewhile the server system remains on-line and powered on. This process iscommonly referred to by the trade as “hot-swapping” of devices. Suchsystems, however, require considerable hands-on intervention of thesystem administrator personnel to manually manipulate the hardwareinterfaces and operating system software for purposes of physically andlogically reintegrating the newly replaced disk device into the diskarray subsystem. Also, the systems capable of hot-swapping, experiencesevere degradation of performance resulting from the process of takingcorrective action.

The process of logical reintegration requires a significant portion ofthe server system central processing unit and memory resources. Theseresources are needed to accomplish the reallocation of the newlyavailable free disk space into the logical disk configuration of theserver and the redistribution of the multiple, duplicate copies of theinformation stored on the server across the new and remaining physicaland logical disk drives. This need for server system resources, althoughtemporary, results in a severe decrease in the performance of theinformation server system.

Thus, users of presently available information server technology havegenerally two types of information server system options available. Thefirst type of server system is completely unavailable for the durationof the system maintenance operation. The second type of system is, ineffect, unavailable to the users due to the seriously degradedperformance experienced by the information server system during thesystem maintenance operation. The following U.S. patents, which arehereby incorporated by reference in their entirety, appear to disclosevarious types and components of the above described information serversystems: U.S. Pat. Nos. 5,402,428; 5,471,099; 5,479,653; 5,502,836;5,517,632; 5,518,418; 5,522,031; 5,530,831; 5,544,339; 5,548,712;5,615,352; 5,651,132; 5,659,677; 5,664,119; 5,666,337; 5,680,538;5,694,581; and 5,701,406.

As a result of the problems and shortcomings of the technologyincorporated into the presently available information server systems,users are left without a satisfactory server system which is capable of,among other features, continuous uninterrupted availability, nondegradedperformance and simplified, quick and easy storage space expansion,reconfiguration, repair and routine maintenance. None of the previousdevices have adequately met these needs. Thus, it is apparent that aneed exists for an system which not only reduces or eliminates theshortcomings and problems associated with the currently availableinformation server systems and related technology, but also whichprovides an efficient and cost-effective solution to such concerns.

SUMMARY OF THE INVENTION

The present invention is an information server system with a “plug andplay”, scalable, modular, fault tolerant, multi-loop, hot swappablearchitecture incorporating a central processing unit, a storage devicecontroller connected to the central processing unit for controlling atleast one storage device array and a communications interface systemconnected to the central processing unit for communicating with othersystems. More particularly, the invention represents a plug and playstorage system for information storage and retrieval applications andincorporates an on board computer server for the storage system, thuseliminating the requirement for resources from a host computer. Thecomputer controls and communicates with a storage device controller anda communications interface with other systems external to the storagesystem. The storage device operates via a high speed interface tocontrol an array of storage devices through their individual hot swapinterface cards.

In one presently preferred embodiment, the invention provides a selfcontained plug and play information server system which incorporates ahigh speed, microcomputer based, server running industry standardoperating system software enhanced to include functionality directed tooperation of an array controller for a storage device such as a magneticdisk array, optical device array, solid state memory or the like, andwhich controls the physically independent or integral storage devicearray, and a communications interface. In a presently preferred form,the array controller subsystem controls and communicates with thestorage device array with a Fibre Channel protocol and topologycompatible 1.0625 gigabit per second copper compact PCI and/or a fibreoptic interface bus and an Intelligent Input/Output, “I₂O” bus forcontrol of and communication with the disk storage device array.

The storage device array incorporates a plurality of storage deviceswith a corresponding number of bypass, or “bridging”, interface cardsconfigured to facilitate the on-line addition, removal and replacementof storage devices. In addition to incorporating the above describedbuses and Fibre Channel capability, the storage device array furtherincorporates a physically independent Fibre Channel compatible opticalbus for high speed communication between storage device array subsystemcomponents, including the internal storage devices, independent from theinformation server. The problems encountered with previously availableinformation server systems are solved by the present invention, whichcan be manufactured relatively inexpensively from a variety ofoff-the-shelf hardware and software, either in standard configurationsor on a custom configured basis. In either configuration, a wide arrayof user reconfigurable options are available as well as a scalableexpansion capability.

The present invention accordingly provides for an information serversystem with a scalable, modular, fault tolerant, hot swappablearchitecture, that comprises a central processing unit; an arraycontroller subsystem connected to the central processing unit forcontrolling at least one storage device array; and a communicationsinterface subsystem connected to the central processing unit forcommunicating with other subsystems of the information server and forcontrolling the array controller subsystem.

For convenience, and not by way of limitation, the invention will bedescribed below in the context of magnetic disk storage devices as theyrepresent readily available and compatible types of storage devices forinformation server applications. However, those skilled in the art willrecognize that other storage devices and media such as optical disks,solid state memories or magnetic storage media would be applicable forvarious applications, depending on the state of development of thestorage media technology and the application to which the system is tobe put. Similarly, the invention will be described in the context of aFibre Channel protocol and topology compatible 1.0625 Gigabit per secondper second copper compact PCI and/or fibre optic interface bus andIntelligent Input/Output I₂O bus as the communications link between thestorage device controller and the storage device array, although othercommunication links may be used, depending on the array architecture,communications speed requirements and available technology for datalinks.

In one presently preferred embodiment, the information server systemfurther comprises a midplane connector for connecting interface cardsfor components. In a currently preferred aspect of the invention, eachdisk storage device array comprises a plurality of disk storage devicesand a corresponding number of bypass interface cards, all of whichcommunicate with one another and the information server. In anotherpresently preferred aspect of the invention, each disk storage devicearray comprises a predetermined number of bypass interface cards whichpopulate the entire information server system, whether or not the entireinformation server system is fully populated with a corresponding numberof disk devices. Each disk storage device is preferably hot-swappable,and each disk storage device is mounted on a bypass interface card thatconnects to the midplane connector.

In a presently preferred embodiment, the disk array controller subsystemcontrols and communicates with one or more disk storage device arrayswith an arbitrated dual channel Fibre Channel system, and each of thedisk storage devices are connected to the arbitrated dual channel FibreChannel architecture, whereby each disk storage device may performsimultaneous reads and writes of data in response to any requests fromthe outside world through the information server. In another presentlypreferred aspect of the invention, the disk storage devices includeelectronic device registration devices, and the disk array controllersubsystem monitors identification numbers of the electronic deviceregistration devices. The disk array controller subsystem can thusmonitor when a component in the information server system is removed oradded. The electronic device registration devices are preferablyintegrated into an electronic circuitry of each of the disk devices suchthat engagement or disengagement of each disk storage device with thedisk storage device array causes a triggering of the electronic deviceregistration devices to generate and transmit a unique identifyingserial number signal unique to each disk storage device to the diskarray controller subsystem. A triggering of the electronic deviceregistration devices preferably causes the electronic deviceregistration devices to generate and transmit a unique identifyingserial number signal unique to each disk device to the disk arraycontroller subsystem, and upon receiving the signal, the disk arraycontroller subsystem then immediately either initiates logicalconnection or disconnection of the disk device to or from the array,depending on whether the disk device has been engaged or disengaged,respectively. The disk array controller subsystem can thus accomplishthe electrical and logical connection and disconnection of the diskdevice by control of the bypass interface cards. In another presentlypreferred aspect, the bypass interface cards comprise an independent butlogically integrated optical bus for communication within the FibreChannel topology and protocol between disk drives.

In another presently preferred embodiment, the disk array controllersubsystem is adapted to configure one or more of the disk storagedevices for a configuration selected from the group consisting of RAID0, RAID 1, RAID 3, RAID 5, RAID 10 and an XOR RAID configuration.

In another presently preferred aspect of this invention, an operator mayactivate a so-called “hot button” which will disable the write functionto the array, thus preventing the writing of suspect data on the storagearray after a system fault has been detected.

From the above, it may be seen that the present invention provides anovel, plug and play, high speed scalable and modular fault tolerantinformation server architecture which offers many benefits over priorart systems. Other features and advantages of the present invention willbecome apparent from the following detailed description of theinvention, taken in conjunction with the accompanying drawings, whichillustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings wherein like reference numerals across theseveral different views refer to identical or corresponding parts,

FIG. 1 is a diagrammatic representation of the Information Server Systemof the present invention;

FIG. 2 is a diagrammatic representation of the Disk Array Controllersubsystem of the Information Server System of FIG. 1; and

FIG. 3 is a is a diagrammatic representation of the Fault Tolerant,Fibre Channel Arbitrated Dual Loop, Hot-Swappable Disk Array subsystemof the Information Server System of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

As can be understood from reference to FIGS. 1-3 in the accompanyingdrawings, which are provided for purposes of illustration and not by wayof limitation, the information server system of the present invention,designated generally by reference numeral 100, incorporates two primarysubsystems, including an information server 200 and a disk storagedevice array 300 connected through its integral Fibre Channelarchitecture compatible, high speed physical and virtual backplane busand Intelligent Input/Output, “I2O” bus to the integral and orindependent and external bus 150. In the presently preferred embodiment,bus 150 is a Gigabit compact PCI/Fibre Channel interface and I₂O Bus,but other optical and copper based high speed data buses and the likeare appropriate, depending upon system throughput requirements andavailable technology. The information server further incorporatessecondary subsystems including, but not limited to, a communicationsinterface subsystem 210, a disk array controller subsystem 230, andsingle board high speed computer 280 running a computer industrystandard operating system software program such as, for example, WindowsNT available from Microsoft Corporation.

The computer further communicates with a display 282, such as a touchscreen display, and a storage device 284 such as a hard disk. Theoperating system software incorporates enhancements adding additionalfunctionality directed to control of the communications interface 210,disk array controller 230 and single board computer 280. The singleboard computer (“SBC”) 280 can include any of a wide number of suitabledevices including, but not limited to, the Compact PCI CPU Board withPentium Processor, Model No. ZT 5510, available from ZiatechCorporation. Modifications to enhance performance of the ZT 5510 caninclude an onboard 40 MB flash memory card for permanent storage of thenon-reconfigurable portions of the Windows NT operating system softwareand an onboard, removable, PCMCIA 40 Mb flash memory card, “D2FlashDisk” available from Sandisk Corporation for read/writeable storageof the reconfigurable portions of the Windows NT software. Therespective manufacturer, Fibre Channel Consortium and I₂O SpecialInterest Group reference design data sheets and materials describing thedetailed operating capabilities and specifications of each of thesecomponents are hereby incorporated by reference in their entirety.

The communications interface subsystem 210 communicates with othersystems on the above described buses and incorporates any combination ofa number of widely available interface and communications tertiarysubsystem circuit boards in the preferred embodiment. The interfaceboards incorporate, among other components, digital subscriber unit(“DSU”) framers which can include, for example, T-1 communicationscompatible DSUs such as the Model No. DS2152 chip set from DallasSemiconductor Corp. The communications boards incorporate, among othercomponents, multi-channel communications processors which can include,for example, the 4-channel “Quick-Chip” communications processor fromMotorola Corp. The communications circuit board also includes onboardbuffer memory and a high speed, Fibre Channel compatible, optical busfor intra-server-component high speed data communications as well asFibre Channel compatible, compact PCI bridge circuitry such as thebridge chip set available from Tundra. Additionally, for improvedcommunications diagnostic, status and health monitoring capabilities,the communications board incorporates a bit error rate tester chip set,such as the device available as Model No. DS2172 from DallasSemiconductor, configured for communication with the SBC 280 andoperating system software, via the I2O bus. Although the communicationsinterface subsystems 210 have been described with reference to wellknown T-1 communications architecture, the subsystems are adaptable forcompatibility with nearly all other network and telecommunicationsarchitectures, protocols and topologies including, but not limited to,T-3, DS-3, OC-3C, OC-12C, OC-192C, FDDI, SONET, SCSI, TCP/IP, HiPPI andATM. The respective manufacturer, consortium, industry association andorganization reference design data sheets and materials describing thedetailed operating capabilities and specifications of each of thesecomponents are hereby incorporated by reference in their entirety.

Referring generally now to the block diagram of FIG. 2, the disk arraycontroller subsystem 230 further incorporates a high speed chip set,such as the ISP2100 Intelligent Fibre Channel Processor available fromQlogic Corp., which includes a reduced instruction set chip (“RISC”)processor 235, a compact PCI interface 240, and a Fibre Channel capable,arbitrated dual loop direct disk access protocol interface 250 formaximum communications bandwidth and redundancy. This controller 230communicates data stored on the disk array or to be stored thereonthrough the communications interface subsystem 210 between the diskarray 300 and the outside world. The controller 230 is fully FibreChannel compliant and is capable of controlling up to 126 disk storagedevices in the disk array 300. The controller 230 is adapted toconfigure the disk array 300 for fault tolerant, data redundancyprotocols including, but not limited to, RAID 0, 1, 3, 5, 10 (1 & 0) andthe new XOR RAID configuration. The respective manufacturer, consortium,industry association and organization reference design data sheets andmaterials describing the detailed operating capabilities andspecifications of each of these components are hereby incorporated byreference in their entirety.

With general reference to FIG. 3, the fault tolerant, Fibre Channelcapable, arbitrated dual loop, hot-swappable disk storage device arraysubsystem 300 further includes an enclosure having a front bay of slotsfor receipt of disk devices 340 and a rear bay for receipt ofbypass/bridging interface cards 370. The midplane of the enclosureincorporates a backbone Fibre Channel compact PCI bus in addition tophysically independent, but logically integrated (within the FibreChannel topology and protocol) I2O and optical buses. The disk array 300also incorporates a plurality of disk storage devices and acorresponding number of bypass interface cards 370, all of whichcommunicate with one another and the information server 200 though anyone or combination of the above described buses. Each disk array 300preferably incorporates a predetermined number of bypass interface cards370 which populate the entire enclosure of the array 300 whether or notthe entire enclosure is fully populated with a corresponding diskdevices 340. Thus, the bypass cards 370 maintain the logical andelectrical integrity of the backbone buses of the array subsystem 300regardless of the number of empty disk device 340 slots.

Each of the disk storage devices 340 may include any number of differentstorage media types including, but not limited to, optical, magneticdisk, magnetic tape, magneto-optical media, flash and bubble memorydevices, compact, read-only disk (“CD-ROM”), digital video disk andother similar technology mass storage devices. In one of the preferredembodiments of the present invention, each of the disk storage devices340 includes a physical interlock system, not shown in the drawings,which is adapted to physically engage and disengage the disk storagedevice 340 to and from a physical enclosure which contains the diskarray 300. Such devices can specifically include, for example, any oneor combination of 4.3 Gb, 9.1 Gb and 18 Gb magnetic disk drivesavailable from Seagate Technologies. Each of the disk devices 340 fullyimplement the arbitrated dual channel Fibre Channel architecture suchthat every disk device 340 may perform simultaneous reads and writes ofdata in response to any requests from the outside world through theinformation server 200. All of such devices of the present inventioninclude, among other components, data carriers known to the trade aselectronic device registration devices.

The data carrier device preferably incorporates a 64-bit ROM with afactory specified, unique 48-bit serial number. This capability enablesunique identification of each and every physical disk device 340manufactured for use with the present invention by any number ofmanufacturers, industry-wide for the foreseeable future. The datacarrier device is integrated into the electronic circuitry of each ofthe disk devices 340 so that as the physical interlock of each diskdevice 340 is actuated to either engage or disengage the disk device 340from the disk array 300, the interlock also triggers the data carrierdevice.

This triggering of the data carrier generates and transmits a uniqueidentifying serial number signal unique to each disk device 340 which istransmitted, for example, over the I₂O bus to the disk controller 230.Upon receiving the signal, the controller 230 then immediately eitherinitiates logical connection or disconnection of the disk device 340 toor from the array 300 depending on whether the disk device 340 has beenengaged or disengaged, respectively. The controller accomplishes theelectrical and logical connection and disconnection of the disk device340 by control of the bypass interface card 370. Use of the data carrierdevice enables remote software controlled logical engagement ordisengagement of each of the disk devices in addition to the abovedescribed operations. Thus, disk device 340 connection or disconnectioncan be accomplished either physically by a system administrator orremotely by error monitoring software functions of either the controller230 or operating system running on the SBC 280. Such data carrierdevices are readily available from a variety of manufacturers includingthe “iButton” available from Dallas Semiconductor as Part No. DS1990A.

The bypass/bridging interface cards 370 which populate the rear bayaccept signals from the controller 230 to communicate via the FibreChannel interface 150 and protocol between the storage devices, thediagnostics and the diagnostics and control system, and interfacing withthe storage devices via the 310 connectors to the storage devices. Thus,each storage device can simultaneously perform multiple reads and writeswithin the arbitrated dual channel Fibre Channel topology and protocolcapability previously described above. This capability allows remotesoftware control to automatically detect insertion of new disk devices340 into the disk array 300, and is thus hot swappable. Thus, automatictesting, formatting, and logical integration can occur without anyintervention of administrator personnel, beyond physical insertion of anew bypass card 370 and/or disk device 340. Accordingly, when a new diskdevice 340 has been detected in the array 300 by receipt of thetransmitted data carrier signal, unattended integration of the new diskinto the array 300 topology is provided. Additionally, no degradation ofthe server system 100 performance will occur, since all such integrationactivity can be performed over the bypass card 370 optical bus. Thecircuitry of the bypass interface cards 370 typically incorporate anyone of a number of Fibre Channel compatible bypass chip sets including,but not limited to, those available from Motorola Corp. as Part No.10SX1189 and Vitesse Semiconductor Corp. as Part Nos. VSC7121 andVSC7122 Bypass Circuits.

For each of the disk storage device array 300 components, the respectivemanufacturer, consortium, industry association and organizationreference design data sheets and materials describing the detailedoperating capabilities and specifications of each of these componentsare hereby incorporated by reference in their entirety.

The method of the invention embodies the control of hot swappableinterface cards and associated storage devices arranged in an array andcontrolled via a high speed interface with a diagnostic and controlsystem containing a communications interface and a storage devicecontroller. A high speed computer dedicated to system control andoperation interfaces with both the communications interface and thestorage device controller to sense and manage the condition of thevarious elements of the storage device array. By utilizing the method ofthe invention, the information server can be in continuous operationwithout the necessity of taking the system down to add storage capacity.

From the above, it will be appreciated that the present inventionrepresents a new and novel arrangement for an information server systemserving a computer information system. The system and method of theinvention provide a plug and play, truly hot swappable storage devicesystem that does not require an external host computer. The system ofthe invention can be directly connected to Fibre Channel networks orEthernet connections. The system provides both hot swappability and hotexpandability for storage device addition and repair without poweringdown or additional diagnostic activities external to the system. Becauseof the scalability and modularity of the architecture, the system can beadapted to virtually any capacity.

While particular forms of the invention have been illustrated anddescribed, it will also be apparent that various modifications can bemade without departing from the spirit and scope of the invention.Accordingly, it is not intended that the invention be limited, except asby the appended claims.

1-26. (Cancelled)
 27. A storage device array system for an informationserver system, the storage device array system comprising: a storagedevice array including a plurality of disk storage devices and at leasta corresponding number of bypass interface cards, all of whichcommunicate with one another; and a storage array controller subsystemfor controlling said storage device array.
 28. The storage device arraysystem of claim 27, wherein said storage device array comprises apredetermined number of bypass interface cards which populate the entirestorage device array whether or not the entire storage device array isfully populated with a corresponding number of storage devices.
 29. Thestorage device array system of claim 27, wherein each said disk storagedevice is hot-swappable.
 30. The storage device array system of claim27, wherein said disk storage devices are selected from the groupconsisting of optical, magnetic disk, magnetic tape, magneto-opticalmedia, flash and bubble memory devices, compact, read-only disk, anddigital video disk storage devices.
 31. The storage device array systemof claim 27, wherein said disk storage devices include electronic deviceregistration devices.
 32. The storage device array system of claim 31,wherein said storage array controller subsystem monitors identificationnumbers of said electronic device registration devices.
 33. The storagedevice array system of claim 31, wherein said storage array controllersubsystem monitors when a component in the information server system isremoved or added.
 34. The storage device array system of claim 31,wherein said electronic device registration devices are integrated intoan electronic circuitry of each of the disk storage devices such thatengagement or disengagement of each disk storage device with the storagedevice array causes a triggering of the electronic device registrationdevices to generate and transmit a unique identifying serial numbersignal unique to each disk storage device to said storage arraycontroller subsystem.
 35. The storage device array system of claim 31,wherein a triggering of said electronic device registration devicescauses said electronic device registration devices to generate andtransmit a unique identifying serial number signal unique to each diskstorage device to said storage array controller subsystem, and uponreceiving the signal, said storage array controller subsystem thenimmediately either initiates logical connection or disconnection of thedisk storage device to or from the storage device array, depending onwhether the disk storage device has been engaged or disengaged,respectively.
 36. The storage device array system of claim 31, whereinsaid storage array controller subsystem accomplishes the electrical andlogical connection and disconnection of the disk storage device bycontrol of said bypass interface cards.
 37. The storage device arraysystem of claim 31, wherein said storage array controller subsystem isadapted to configure said disk storage device for fault tolerant, dataredundancy protocols.
 38. The storage device array system of claim 37,wherein said storage array controller subsystem is adapted to configuresaid disk storage device for a configuration selected from the groupconsisting of RAID 0, RAID 1, RAID 3, RAID 5, RAID 10 and an XOR RAIDconfiguration.